[R] Help rewriting looping structure?

[Law, Jason]

This will give you the percents in the same order as your original data (as
this is what your original code did)

apply(tdat, 2,
function(x) {
	o <- order(x)
	oldo <- order(o)
	prc <- cumsum(x[o]) / sum(x)
	prc[oldo]
})

Jason Law
Statistician
City of Portland, Bureau of Environmental Services
Water Pollution Control Laboratory
6543 N Burlington Avenue
Portland, OR 97203 -5452
jlaw at bes.ci.portland.or.us



-----Original Message-----
From: r-help-bounces at r-project.org
[mailto:r-help-bounces at r-project.org]On Behalf Of TLowe
Sent: Thursday, December 06, 2007 10:28 AM
To: r-help at r-project.org
Subject: Re: [R] Help rewriting looping structure?



Thank you all.  That's exactly what I was looking for.



TLowe wrote:
> 
> Hey Folks,
> 
> Could somebody help me rewrite the following code?
> 
> I am looping through all records across 5 fields to calculate the
> cumulative
> percentage of each record (relative to each individual field).
> 
> Is there a way to rewrite it so I don't have to loop through each
> individual
> record?
> 
> ##### tdat is my data frame
> ##### j is my field index
> ##### k is my record index
> ##### tsum is the sum of all values in field j
> ##### tmp is a vector containing the values in field j
> ##### tdat[k,paste("cpct,j,sep="")] creates new fields "cpct1",...,"cpct5"

> 
> 
> for(j in 1:5) {
>   tsum<- sum(tdat[,j]);
>   for(k in 1:nrow(tdat)) {
>     td<- tdat[k,j];
>     tmp<-tdat[,j];
> ##### sum values <= to current value and divide by the total sum
>     tdat[k,paste("cpct,j,sep="")]<- sum(tmp[tmp <= td]) / tsum;
>   }
> }
> 
> 
> Thanks,
> TLowe
> 

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